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A323505
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Mirror image of (denominators of) Bernoulli tree, A106831.
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9
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1, 2, 4, 6, 8, 12, 12, 24, 16, 24, 24, 48, 24, 36, 48, 120, 32, 48, 48, 96, 48, 72, 96, 240, 48, 72, 72, 144, 96, 144, 240, 720, 64, 96, 96, 192, 96, 144, 192, 480, 96, 144, 144, 288, 192, 288, 480, 1440, 96, 144, 144, 288, 144, 216, 288, 720, 192, 288, 288, 576, 480, 720, 1440, 5040, 128, 192, 192, 384, 192, 288, 384, 960, 192, 288, 288
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OFFSET
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0,2
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COMMENTS
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In contrast to A106831 which follows Woon's original indexing (and orientation), this variant starts with value a(0) = 1, with the rest of terms having an index incremented by one, thus allowing for a simple recurrence.
Sequence contains only terms of A001013 and each a(n) is a multiple of A246660(n).
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LINKS
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FORMULA
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a(0) = 1; and for n > 0, if n is even, a(n) = 2*a(n/2), and if n is odd, a(n) = (A001511(n+1)+1-A036987(n)) * a((n-1)/2).
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EXAMPLE
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This sequence can be represented as a binary tree:
1
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...................2....................
4 6
8......../ \........12 12........./ \.......24
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
16 24 24 48 24 36 48 120
32 48 48 96 48 72 96 240 48 72 72 144 96 144 240 720
etc.
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PROG
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(PARI)
(PARI)
A106831r1(n) = if(!n, 1, if(n%2, 2*A106831r1((n-1)/2), (1+A001511(n))*A106831r1(n/2))); \\ Recurrence for A106831, when prepended with 1, thus shifted one term right
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CROSSREFS
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KEYWORD
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nonn,tabf
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AUTHOR
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STATUS
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approved
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